Gasket type determines whether or not you need to retorque. New cars have
gaskets designed not to require retourque. If you use a shim steel gasket,
or a copper one, you don't need to retorque.
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
Of Mike
Sent: Thursday, April 07, 2005 6:26 AM
To: fot@autox.team.net
Subject: re-torque cyl heads
Well it seems my post about where to buy gasoline 'sparked' a very
interesting thread. Lots of info that shows the broad knowledge base of this
group. So, here's another.
We just finished rebuilding the V-12 in an XJS (why, you might ask). At
one point we told the customer that we had driven the car and were now going
to re-torque the cylinder heads. She assumed that we had done something
wrong and needed to correct it. We explained about heat-cycles and re-torque
and she understood, but asked why she had never had to have the heads
re-torqued on her other (new) cars.
I've rebuild countless engines over the last 30-40 years and always
retorqued the heads after a heat cycle. Sometimes, like with a Stag, we
might re-torque 10 times before things stop moving.
Everybody in the shop (7 guys) agree that you always re-torque after a
rebuild. How come new engines don't need to be re-torqued? I've never heard
of taking a car back for it's 1000 mile re-torque. Maybe they did this years
ago, pre-war?, but I don't know.
Does everybody always retorque? On a race engine? Why don't new engines
need this? Only the cylinder head? Inquiring minds want to know, plus I'd
like to be able to give my client an answer.
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